Something else a bit weird, not sure if it's related:
# yum check all
Loaded plugins: presto, refresh-packagekit
nss-softokn-3.12.4-19.fc13.x86_64 is a duplicate with
nss-softokn-3.12.4-17.fc13.i686
nss-softokn-freebl-3.12.4-19.fc13.x86_64 is a duplicate with
nss-softokn-freebl-3.12.4-17.fc13.i686
Error: check all